Two-channel semiconductor component

ABSTRACT

A two-channel semiconductor component has a doped semiconductor body formed from a group IV semiconductor material, a top-side top-gate electrode, and a bottom-side bottom-gate electrode. A source region has a greater extent in a depth direction in the silicon body than a drain region. A source isolation region is arranged between a source region and the top-gate electrode, and a drain isolation region is arranged between a drain region and the top-gate electrode, which isolation region extends in a depth direction as far as to the lower edge of a gate isolation layer of the top-gate electrode. In a first operating state a first conductive channel separated laterally from the source region by the source isolation region can be formed, as can a second conductive channel, which is decoupled from the first conductive channel by a barrier region of the semiconductor body extending in a depth direction between the conductive channels. In a second operating state which satisfies a resonance condition, the first and second conductive channel can be coupled to one another by means of a tunnel effect for minority charge carriers over the barrier region of the semiconductor body.

The present invention relates to a semiconductor component with twospatially separated conductive channels. Such components are alsoreferred to as two-channel semiconductor components.

The generation and gate control of conductive channels in semiconductorcomponents by means of the field effect is well known from field effecttransistors and is technologically highly developed in these componentsin various forms. Components with two spatially separated channels forma special group. They are suitable for use as particularly fast switchesand as signal mixers. It shall be noted that, instead of the term“conductive channel”, the present application also uses the terms“conduction channel” or simply “channel” with the same meaning.

In known two-channel components with gate control, coupling between theconductive channels can be achieved by means of a resonant tunneleffect. Such known two-channel components differ in the dimensionalityof the conduction channels, i.e. in the spatial limitation of the chargecarrier mobility in the conduction channels to one level or one line, inthe contacting of the conduction channels and in the respectively usedmaterial system.

As material system, prior art uses III-V semiconductor heterostructures,e.g. GaAs/AlGaAs, on the one hand, and CMOS-compatible andtherefore—from a technological and economic point of view—particularlyinteresting semiconductor/oxide structures, such as Si/SiO2 structures.

Since GaAs/AlGaAs heterostructures can be produced epitaxially, the wavefunctions of their charge carriers have long coherence lengths, and one-and two-dimensional charge carrier gases can be used as channels.

Furthermore, in known III-V semiconductor heterostructures, the optionof selective (separated, i.e. non-parallel) contacting of thesource/drain electrode by means of so-called depletion gates, which areprovided in addition to the respective control gate, was realized. Arespective depletion gate is provided for each channel. Through theapplication of a suitable voltage to a corresponding depletion gate, theassigned channel is depleted locally—below or above the depletiongate—of free charge carriers and thus interrupted and separated from theadjacent source or drain contact. As long as the separation exists, theseparated contact is only connected to the respective other channel.

The depletion gate method used in III-V semiconductors requires abarrier between the conduction channels, for example in the form of anAlGaAs separation layer between GaAs channels. Without such a barrier, adepletion voltage at a depletion gate would only lead to an undesiredmerging of the two conduction channels.

The lateral component dimensions achieved with a depletion gate in theIII-V material system are in the micrometer range, which, compared tothe current state of silicon-based CMOS technology, isdisproportionately large.

Significant progress with regard to the miniaturization of thecomponents, with a channel length of down to approx. 10 nm, wereachieved in the field effect or bipolar transistors customary in massproduction through the material system of the group IV semiconductors,which forms the backbone of the CMSO technology. However, a barrierbetween the conduction channels, as used in multi-channel componentsusing III-V semiconductors, is not correspondingly available insilicon-based CMOS technology. In addition, it would be desirable to beable to also realize a four-pole geometry in a two-channel semiconductorcomponent.

US 2017/0098716 A1 shows a field effect transistor consisting oftwo-dimensional monolayers separated by an interlayer, which makes itpossible to tunnel charge carriers.

US 2014/0014905 A1 describes a field effect transistor that includes agraphene channel layer on a substrate.

The present invention now proposes an improved two-channelsemi-conductor component having

-   -   a doped semiconductor body formed from a group IV semiconductor        material;    -   a top-side top-gate electrode;    -   a bottom-side bottom-gate electrode,    -   a first source electrode with a doped first source region of a        second conductivity type—that is opposite to the first        conductivity type—formed in the semiconductor body,    -   a first drain electrode with a doped first drain region of the        second conductivity type formed in the semiconductor body;        wherein    -   the first source region has a greater extent in a depth        direction in the silicon body than the first drain region, and        divides the semiconductor body into a first depth section, that        extends as far as to a lower edge of the first drain region, and        a second depth region, that extends in a depth direction        adjacently to the first depth section as far as to the bottom        side of the semiconductor body;    -   from a lateral point of view, a first source isolation region is        arranged between a first source region and the top-gate        electrode, wherein said first source isolation region        electrically isolates the source electrode and the top-gate        electrode from each other and extends in a depth direction into        the first depth section of the semiconductor body, but not into        the second depth section;    -   from a lateral point of view, a first drain isolation region is        arranged between the first drain region and the top-gate        electrode, wherein said first drain isolation region        electrically isolates the drain electrode and the top-gate        electrode from each other and extends in a depth direction as        far as to the lower edge of the gate isolation layer; wherein    -   the respective dimensions of the first source region, of the        first drain region, of the first source isolation region and of        the first drain isolation region in a depth direction are chosen        such that        -   in a first operating state, in which respective first and            second operating voltages are applied to the top-gate            electrode and the bottom-gate electrode, a first conductive            channel of the second conductivity type, which is separated            laterally from the first source region by the source            isolation region, can be formed in the first depth section,            and a second conductive channel of the second conductivity            type, which is decoupled from the first conductive channel            by a barrier region of the semiconductor body extending in a            depth direction between the conductive channels, can be            formed in the second depth section, and        -   in a second operating state, in which third and fourth            operating voltages satisfying a resonance condition are            applied to the top-gate electrode and the bottom-gate            electrode, the first and second conductive channel can be            coupled to one another by means of a tunnel effect for            minority charge carriers over the barrier region of the            semiconductor body.

The design of a two-channel semiconductor component according to theinvention provides for a special form of selective contacting of thechannels, which, while it is not known from traditional CMOS-compatiblefield effect transistors, is compatible with the CMOS technology evenwith the high scaling customary in industrial production today. Theseare significant improvements compared to the aforementioned, previouslyrealized selectively contacted two-channel systems in the GaAs/AlGaAsmaterial system with channel lengths of more than 1 μm.

In the two-channel semiconductor component according to the invention,the first source region has a greater extent in a depth direction in thesemiconductor body than the first drain region. Thus, the semiconductorbody can be divided into two depth sections, namely

-   -   into a first depth section extending as far as to a lower edge        of the first drain region, and    -   into a second depth section extending in a depth direction        adjacently to the first depth section as far as to the bottom        side of the semiconductor body;

From a lateral point of view, a first source isolation region isarranged between a first source region and the top-gate electrode,wherein said first source isolation region electrically isolates thesource electrode and the top-gate electrode from each other. It extendsin a depth direction into the first depth section of the semiconductorbody, but not into the second depth section. From a lateral point ofview, a first drain isolation region is at the same time arrangedbetween the first drain region and the top-gate electrode, wherein saidfirst drain isolation region electrically isolates the drain electrodeand the top-gate electrode from each other and extends in a depthdirection as far as to the lower edge of the gate isolation layer. Thisallows for the formation of a channel that is in direct contactexclusively with the drain electrode—i.e. is separated laterally fromthe first source region by the first source isolation region—in thefirst depth section.

At the same time, a suitable choice of the respective dimensions of thefirst source region, of the first drain region, of the first sourceisolation region and of the first drain isolation region in a depthdirection, allows for the formation of a second conductive channel ofthe second conductivity type—which is decoupled from the firstconductive channel by a barrier region of the semiconductor bodyextending in a depth direction between the conductive channels—in thesecond depth section. What is essential in this regard is the alreadymentioned feature of the two-channel semiconductor component accordingto the invention that the first source region has a greater extent in adepth direction in the semiconductor body than the first drain region.The second conductive channel, that is controllable via the bottom-gateelectrode on the bottom side, is therefore formed such that it is indirect contact only with the source electrode.

Thus, this design ensures that the charge carrier transport from thesource electrode to the drain electrode can only take place through theresonant tunneling of charge carriers through the formed barrier regionin accordance with the laws of the quantum mechanical tunnel effect.This quantum mechanical tunnel coupling between the conductive channelsin the two-channel semiconductor component according to the inventionshows a resonance behavior also at a shorter channel length, even in therange of a channel length of approximately 10 nm. As a result, thechannels can be completely coupled or decoupled with very small changesin the top-gate voltage and bottom-gate voltage, if the resonance issharp. In case of the present coupling, very few charges flow in theshort channels over short distances, which promotes a high switchingspeed with a small power loss.

Thus, the two-channel semiconductor component according to the inventionrealizes a lateral current transport between source and drain electrodesby means of transversal resonant tunneling of charge carriers betweenthe conductive channels.

It needs to be mentioned that, as a general rule, the functions of thesource and drain regions in the two-channel component according to theinvention are interchangeable, so that therefore the functionalassociation of electrodes, semiconductor regions and isolation regionswith the source or drain chosen above is also interchangeable. However,for the sake of the clarity of the description, the above associationwill be applied in the form chosen above also to the furtherdescription; however, this does not imply any limitation of the presentinvention.

In the following, exemplary embodiments of the two-channel semiconductorcomponent according to the invention are described.

In one embodiment, the two-channel semiconductor component is configuredas a two-terminal component.

In preferred embodiments, the conduction channels have a channel lengthof less than 30 nm. As known from traditional field effect transistors,the channel length refers to the lateral distance in the semiconductorbody that charge carriers bridge between the source and the drain regionat the conductivity controlled by the respective gate electrode. Specialembodiments that can be achieved by means of particularly highly scaledCMOS technology have a channel length of less than 20 nm, for example 10nm, or even only between 5 and 10 nm. With—per se—known moderntechnologies, a channel length of only 5 nm can be achieved.

An example of a suitable dopant concentration in the conductive channelsis 10¹⁵ cm⁻³. However, higher or lower values, preferably in the rangebetween 10¹⁴ cm⁻³ and 10¹⁶ cm⁻³, can also be used.

In preferred embodiments, the extent of the barrier region in a depthdirection, i.e. the distance between the conductive channels that mustbe bridged through resonant tunneling in the second operating state, isbetween 10 and 30 nm, preferably approximately 20 nm. This distance canbe set in a targeted manner during the design process of the two-channelcomponent through the specification of the dopant concentration in thebarrier region. The higher the dopant concentration in the barrierregion, the smaller a distance of the barrier region can be chosen. Anincreased dopant concentration changes the energetic level of thebarrier to be tunneled.

As a general rule, both gate electrodes must be operated in a homopolarmanner during the operation of the two-channel component. At a set biasvoltage of the bottom-gate electrode, the satisfaction of the resonancecondition for the second operating state becomes apparent in thetwo-channel component when the voltage at the top-gate electrode is “runthrough” a peak of the drain current. The bias voltage at thebottom-gate electrode can be used to adjust the energetic level of thetunnel barrier over a certain range. An energetically higher tunnelbarrier provides a sharper resonance, which is shown by a peak of thedrain current in a smaller interval of the voltage at the top-gateelectrode. In case of an energetically higher tunnel barrier, the peakof the drain current has a smaller maximum amplitude than in case of alower tunnel barrier. In one embodiment, where the two-channelsemiconductor component is realized as a four-terminal component, itfurther comprises

-   -   a second source region which is laterally arranged between the        first source region and the top-gate electrode, has a smaller        extent in a depth direction than the first source region and is        laterally electrically isolated from the first source region by        the first source isolation region, and which is laterally        electrically isolated from the top-gate electrode by a second        source isolation region, and    -   a second drain region, which, from a lateral point of view, is        arranged at a greater distance from the top-gate electrode than        the first drain region, has a greater extent in a depth        direction than the first drain region and is laterally        electrically isolated from the first drain region by a second        drain isolation region and which extends into the second depth        section.

In this embodiment, the respective dimensions of the first and secondsource region, of the first and second drain region, of the first andsecond source isolation region and of the first and second drainisolation region in a depth direction are preferably chosen such thatthe first conductive channel extends in the lateral direction betweenthe second source region and the first drain region, and that the secondconductive channel extends in the lateral direction between the firstsource region and the second drain region.

In one exemplary embodiment, the two-channel semiconductor component isused as part of a signal mixer which has a two-channel semiconductorcomponent according to the invention or one of its embodiments, which issupplied a first input signal via the bottom-gate electrode, which issupplied a second input signal via the source electrode, and at thedrain electrode of which an output signal can be picked up via an outputresistance.

In another embodiment, the two-channel semiconductor component is usedas a tunable detector for electromagnetic waves. In this embodiment, atunable sensitivity of the drain current to electromagnetic waves inaccordance with a correspondingly determined energy can be achievedthrough the tuning of the bottom- and top-gate voltage. In thisembodiment, the resonance condition is satisfied by the sum of a presetstatic energetic component in the form of the two gate voltages and adynamic energetic component in the form of the energy of theelectromagnetic waves with the wavelength to be detected radiated intothe semiconductor body. The more intensely the light of this wavelengthradiates, the higher the detected drain current will be.

In the following, further exemplary embodiments will be described withreference to the accompanying figures. The following is shown in

FIG. 1 a schematic illustration of a two-channel semiconductor componentwith two gated tunnel-coupled conduction channels;

FIGS. 2 and 3 illustrations showing charge carrier wave functions in thearea of the conduction channels of the two-channel semiconductorcomponent of FIG. 1 in case of a resonant coupling of the conductionchannels (FIG. 2) and in case of decoupled conduction channels (FIG. 3);

FIG. 4 a schematic illustration of the two-channel semiconductorcomponent of FIG. 1 with parallel contacting of the source and drainelectrodes for parallel controlling of both conduction channels;

FIG. 5 a schematic illustration of a two-channel semiconductor componentwith selective contacting of respectively one source or drain electrodefor separate controlling of the conduction channels;

FIG. 6 a schematic illustration of a two-channel semiconductor componentconfigured as a four-terminal component with selective contacting ofrespectively both source or drain electrodes for separate controlling ofthe conduction channels;

FIG. 7 a schematic cross-sectional view of a two-channel semiconductorcomponent with selective contacting of respectively one source or drainelectrode for separate controlling of the conduction channels;

FIG. 8 a schematic cross-sectional view of a two-channel semiconductorcomponent configured as a four-terminal component with selectivecontacting of respectively both source or drain electrodes for separatecontrolling of the conduction channels;

FIG. 9 a schematic cross-sectional view of the two-channel semiconductorcomponent of FIG. 7 with circuitry for forming a signal mixer;

FIG. 10 an exemplary signal of a local oscillator voltage ΔU(t) as afunction of the time that can be supplied to the signal mixer of FIG. 9;

FIG. 11 an exemplary signal of a high-frequency signal U_(D)(t) as afunction of the time that can be supplied to the signal mixer of FIG. 9;

FIG. 12 an output signal of the signal mixer of FIG. 9.

FIG. 1 shows a schematic illustration of a two-channel semiconductorcomponent with two gated tunnel-coupled conduction channels. Asemiconductor body in the form of a silicon body 102 forms a substrate,on the top side of which a top-gate electrode 104 is formed and on thebottom side of which a bottom-gate electrode 106 is formed. Instead ofsilicon, germanium or silicon-germanium may also be used assemiconductor body.

In the following, more details regarding the substrate formed by thesilicon body 102, the top-gate electrode 104 and the bottom-gateelectrode 106 will be explained.

In the state shown in FIG. 1, two n-conductive channels 102.1 and 102.2are formed in the silicon body 102, which, as such, consists of p-dopedsilicon, wherein the n-conductive channels 102.1 and 102.2 extendbetween the source and drain electrodes—which are not shown in FIG.1—and are, in the following, also in short referred to as conductionchannel 1, 2 or LK1, LK2. Further details on the different options forforming the source and drain electrodes as well as on the circumstances,under which the conduction channels 1 and 2 are formed are providedfurther below.

A depth direction T points from the top side O of the silicon body 102to the bottom side U, i.e. in the stacking direction of the illustratedlayered arrangement. In this depth direction, the silicon body 102 formsa barrier 102.2 between the conduction channels 102.1 and 102.2.

The top-gate electrode 104 is formed of an electrically conductive layer104.1 on a top-gate isolation layer 104.2 made of dielectric material.The gate isolation layer 104.2 rests on the top side of the silicon body102.

The bottom-gate electrode 106 is formed of an electrically conductivelayer 106.1 on a bottom-gate isolation layer 106.2 made of dielectricmaterial. The bottom-gate isolation layer 106.2 rests on the bottom sideof the silicon body 102.

FIGS. 2 and 3 show illustrations showing charge carrier wave functionsin the area of the conduction channels of the two-channel semiconductorcomponent of FIG. 1 in case of a resonant coupling of the conductionchannels (FIG. 2) and in case of decoupled conduction channels (FIG. 3).In addition to the conductive channels 102.1 and 102.2 and the barrierregion 102.3, FIG. 2 shows in the silicon body in schematic form quantummechanical wave functions WF+ and WF− of charge carriers. Thelocation-dependent illustration shows the amplitudes of the wavefunctions at the respective location within the shown area of thesilicon body 102.

As generally known, a probability with which a particle is at a certainlocation can be derived from the amplitude of the quantum mechanicalwave functions. In case of FIG. 2, both wave functions WF+ and WF−respectively show two extreme values, namely within the two conductionchannels 102.1 and 102.2, and reduced amplitudes in the area of thebarrier 102.3. This corresponds to the desired coupling state betweenthe conduction channels 102.1 and 102.2, which is expressed by theillustrated de-localized wave functions WF+ and WF+. In this case, theprobability with which the individual charge carriers are at a certainlocation is simultaneously distributed over both channels. Thiscorresponds to a situation in which a resonant tunnel effect is createdby appropriately selected control voltages UG1 and UG2 applied to thetop and bottom gate. This means that, in the illustrated resonance case,the conduction channels 102.1 and 102.2 are coupled, since the chargebarriers between them are able to tunnel through the barrier 102.3, sothat a charge carrier tunnel current is able to flow between theconduction channels.

FIG. 3, as well, shows, in addition to the conductive channels 102.1 and102.2 and the barrier region 102.3 in the silicon body, in a schematicform quantum mechanical wave functions WF+ and WF− of electrons, howeverfor the case in which the conduction channels 102.1 and 102.2 aredecoupled from each other, which, in turn, can be achieved throughappropriately selected control voltages UG1 and UG2.

The location-dependent illustration of the wave functions shows that theamplitudes of the wave functions of electrons are localized within theconduction channels 102.1 and 102.2 and do not extend into therespective other conduction channel. This corresponds to a decoupledstate between the conduction channels 102.1 and 102.2, which isexpressed by the illustrated strongly localized wave functions WF+ andWF−. In this case, the probability with which the individual chargecarriers are at a certain location is also strongly limited to one ofthe two conduction channels. This corresponds to a situation in which aresonant tunnel effect is prevented by appropriately selected controlvoltages UG1 and UG2 applied to the top and bottom gate.

Thus, switching between the two states of FIGS. 2 and 3—coupled anddecoupled—can be achieved by appropriately selected control voltages UG1and UG2 at the top- and bottom-gate electrode.

In the following, different versions of contacting are shown for thetwo-channel component illustrated in FIG. 1 by means of FIGS. 4 to 6.

FIG. 4 shows a schematic illustration of a first version 100′ of thetwo-channel semiconductor component of FIG. 1 with parallel contactingof the source and drain electrodes for parallel controlling of bothconduction channels. In case of this form of contacting, a sourceelectrode 108 and a drain electrode 110 are each in direct contact withboth conduction channels 102.1 and 102.2. In this version, a chargecarrier current can also flow when the control voltages UG1 and UG2applied do not create a resonant tunnel effect, i.e. when the conductionchannels are decoupled.

FIG. 5 shows a schematic illustration of a second version 100″ of thetwo-channel semiconductor component of FIG. 1 with selective contacting,i.e. where, in the decoupled state, a source electrode 118 is onlyconnected to the first conduction channel 102.1, and a drain electrode120 is, in the decoupled state, only connected to the second conductionchannel 102.2. Thus, in this case, a charge carrier current can flowbetween the source electrode 108 and the drain electrode only ifsuitable control voltages UG1 and UG2 are applied for setting a resonanttunnel effect.

FIG. 6 shows a schematic illustration of a third version 100′″ of thetwo-channel semiconductor component of FIG. 1, which is configured as afour-terminal component. In each case, two source electrodes 128.1 and128.2 that can be controlled electrically separately from each other,and two drain electrodes 130.1 and 130.2 that can be controlledelectrically separately from each other allow for separate controllingof the conduction channels 102.1 and 102.2 in different caseconstellations. These constellations are explained in more detail below.

FIG. 7 shows a schematic cross-sectional view of a two-channelsemiconductor component 700 that provides for selective contacting ofrespectively one source or drain electrode for separate controlling oftwo conduction channels, in accordance with the version shown in FIG. 5.In this document, this type of contacting is also referred to as“diagonal contacting”. The structure of the two-channel semiconductorcomponent 700 is explained below.

The two-channel semiconductor component 700 has a p-doped silicon body702, wherein a top-gate electrode 704 is arranged on the top side of thesilicon body 702 and a bottom-gate electrode 706 is arranged on thebottom side of the silicon body 702. The top-gate electrode 704 iscomposed of an electrically conductive layer 704.1 on a top-gateisolation layer 704.2 made of dielectric material. The gate isolationlayer 704.2 rests on the top side of the silicon body 702, which isstructured for this purpose. The silicon body 702 is laterallystructured, as will be explained in more detail further below. Thebottom-gate electrode 706 is formed of an electrically conductive layer706.1 on a bottom-gate isolation layer 706.2 made of dielectricmaterial. The bottom gate isolation layer 706.2 rests on the bottom sideof the silicon body 102 and extends laterally across the entire bottomside of the silicon body 702. Likewise, the electrically conductivelayer 706.1 that rests on the bottom gate isolation layer 706.2 extendslaterally across the entire bottom side of the silicon body 702.

A source electrode has a doped source region 708 of the n-conductivitytype, which is formed in the silicon body 702. Additional structuralelements of the source electrode, in particular for contacting thesource region, are—for the sake of the simplicity of theillustration—not shown in FIG. 7. They can be produced by means of knownmethods of CMOS technology.

A drain electrode has a doped drain region 710 of the n-conductivitytype, which is formed in the silicon body 702.

As can be clearly seen in FIG. 7, the source region 708 has an extent TSin a depth direction T in the silicon body 702 which is greater than theone of the drain region 710, which, accordingly, has a smaller extent TDin a depth direction. The extent TD in a depth direction correspondsapproximately to the doping depth of a source/drain region that iscustomary for the CMOS technology used. The comparatively greater extentTS in a depth direction of the source region 708 divides the siliconbody 702 for the purposes of the following explanation into a firstdepth section I, that extends from the surface of the silicon body 702to a lower edge of the source region 708, i.e. that corresponds to theextent TS in a depth direction of the source region, and into a seconddepth section II, that extends in the depth direction T adjacently tothe first depth section I as far as to the bottom side of the siliconbody 702. As explained above, the bottom gate isolation layer 706.2rests on the bottom side of the silicon body 702 and can therefore notbe considered to be part of the silicon body 702.

In the following, the structure of the top-gate electrode 704 in itsenvironment is explained in more detail. From a lateral point of view, asource isolation region 712 is arranged between the source region 708and the top-gate electrode 704, wherein the source isolation region 712electrically isolates the source region 708 and the top-gate electrode704 from each other. An extent TIS in a depth direction of the sourceisolation region 712 extends into the first depth section I of thesilicon body and beyond the extent TS in a depth direction of the drainregion 710, but does not extend into the second depth section II. Thus,the source isolation region has an extent TIS in a depth direction thatis greater than the one of the drain region 710, but smaller than theone of the source region 708.

From a lateral point of view, a drain isolation region 714 is arrangedbetween the first drain region 710 and the top-gate electrode 704,wherein the drain isolation region 714 electrically isolates the drainregion 710 (and the entire drain electrode along with it) and thetopgate electrode 704 from each other. The extent TID in a depthdirection T of the drain isolation region 714 extends as far as to thelower edge of the gate isolation layer, and also as far as to the loweredge of the drain region 710. Thus, the gate isolation region isarranged in a recess formed in the silicon body 702.

The dimensions of the source region 708, the drain region 710, thesource isolation region 712 and the drain isolation region 714 in adepth direction are chosen such that, during the operation of thetwo-channel semiconductor component, a first conduction channel 702.1 isformed below the top-gate electrode 704 and a second conduction channel702.2, that is separated from the first conduction channel 702.1, isformed above the bottom-gate electrode 706 in the silicon body 702, whensuitable control voltages UG1 and UG2 (cf. FIG. 1) are available at thetop-gate electrode 704 and the bottom gate electrode 706. The twoconduction channels 702.1 and 702.2 are separated from each other by abarrier region 702.3 of the silicon body 702, which is formed whensuitable gate voltages are chosen.

This means that, when respective suitable first and second operatingvoltages UG1 and UG2 are applied to the top-gate electrode 704 and thebottom-gate electrode 706, the first conductive channel 702.1 of then-conductivity type, which is laterally separated from the source region708 by the source isolation region 712, is formed in the first depthsection I. The extent in a depth direction of said first conductivechannel 702.1 can be influenced via the control voltage UG1 applied tothe top-gate electrode 704. This conductive channel 702.1 does not haveany direct contact with the source region 708, since, in a depthdirection T, it does not extend as far as the lower edge of the sourceisolation region 712, but ends slightly higher up in the silicon body702. Therefore, the n-doped source region 708 laterally adjoins thebarrier region 702.3 of the p-doped silicon body below the sourceisolation region 712. During operation, charge carriers are not able topass the thus created barrier zone at the interface between the siliconbody 702 and the source region 708.

Furthermore, in this state, where said first and second operatingvoltages UG1 and UG2 are applied to the top-gate electrode 704 and thebottom-gate electrode 706, a second conductive channel 702.3 of then-conductivity type is formed in the second depth section II of thesilicon body 702. The extent in a depth direction of said secondconductive channel 702.3 can be influenced via the control voltage UG2applied to the bottom-gate electrode 706. To put it more specifically:the voltage applied to the bottom-gate electrode 706 influences how farthe second conductive channel 702.2 extends “upwards”—in the directionof the top side of the silicon body—from the bottom side of the siliconbody 702. The second operating voltage UG2 is chosen such that thesecond conductive channel is only formed below the source region 708,but preferably extends as far as directly to the lower edge of thesource region 708.

Depending on the chosen operating voltages UG1 and UG2, the followingoperating states, in particular, can be set:

-   -   a) in a first operating state, in which respective first and        second operating voltages are applied to the top-gate electrode        704 and the bottom-gate electrode 706, a first conductive        channel 702.1, which is separated laterally from the source        region 708 by the source isolation region 712, is formed in the        first depth section, and a second conductive channel 702.2,        which is decoupled from the first conductive channel by a        barrier region 702.3 of the silicon body 702 extending in a        depth direction between the conductive channels, is formed in        the second depth section. This operating state corresponds to        the state shown in FIG. 3. In this operating state, no charge        carriers can flow between the source region 708 and the drain        region 710.    -   b) in a second operating state, in which third and fourth        operating voltages satisfying a resonance condition are applied        to the top-gate electrode 704 and the bottom-gate electrode 706,        the first and second conductive channel 702.1 and 702.2 can be        coupled to one another by means of a tunnel effect for electrons        over the barrier region 702.3 of the silicon body. This means        that only in the second operating state can charge carries flow        between the source region 708 and the drain region 710, namely        through the second conductive channel 702.2, by means of the        tunnel effect through the barrier region 702.3, and through the        first conductive channel 702.1.

Thus, the two-channel semiconductor component 700 forms a controllableswitch. Said switch is characterized in that, if a sharp resonance ispresent, switching can be achieved with very small changes in thevoltage of the control voltages. This means that, on the one hand, smallswitching current with small power losses, i.e. with little heating, areachieved, and, on the other, particularly short switching times.

The structure of the semiconductor component is suitable for integrationinto existing CMOS technologies and can be scaled accordingly.Preferably, a SOI wafer can be used for the manufacture of thesemiconductor component. The choice of material for the individuallayers, in particular of the gate electrodes of the isolation layersetc., may be made in accordance with a respectively used CMOStechnology. Therefore it is, in particular, dictated by the scalingachieved by the respective CMOS technology, i.e. by thetechnology-dependent minimum structure width.

FIG. 8 shows a schematic cross-sectional view of a two-channelsemiconductor component 800 configured as a four-terminal component withselective contacting of respectively both source or drain electrodes forseparate controlling of the conduction channels.

The two-channel semiconductor component 800 has a p-doped silicon body802, wherein a top-gate electrode 804 is arranged on the top side of thesilicon body 802 and a bottom-gate electrode 806 is arranged on thebottom side of the silicon body 802. The top-gate electrode 804 iscomposed of an electrically conductive layer 804.1 on a top-gateisolation layer 804.2 made of dielectric material. The gate isolationlayer 804.2 rests on the top side of the silicon body 802, which isstructured for this purpose. The silicon body 802 is laterallystructured, as will be explained in more detail further below. Thebottom-gate electrode 806 is formed of an electrically conductive layer806.1 on a bottom-gate isolation layer 806.2 made of dielectricmaterial. The bottom gate isolation layer 806.2 rests on the bottom sideof the silicon body 802 and extends laterally across the entire bottomside of the silicon body 802. Likewise, the electrically conductivelayer 786.1 that rests on the bottom gate isolation layer 806.2 extendslaterally across the entire bottom side of the silicon body 802.

A first source electrode has a doped first source region 808 of then-conductivity type, which is formed in the silicon body 802. Additionalstructural elements of the source electrode, in particular forcontacting the source region, are—for the sake of the simplicity of theillustration—not shown in FIG. 8. They can be produced by means of knownmethods of CMOS technology.

A first drain electrode has a doped drain region 810 of then-conductivity type, which is formed in the silicon body 802.

In addition to these structural elements that are also comprised by thetwo-channel component 700 of FIG. 7. the exemplary embodiment of FIG. 8has a second source region 818. Said second source region 818 isarranged laterally between the first source region 808 and the top-gateelectrode 804. The second source region 818 has a smaller extent in adepth direction than the first source region 808. In this case, theextent in a depth direction corresponds to the one of the first drainregion 810.

There is also a second drain region 820. Said second drain region 820is, from a lateral point of view, arranged at a greater distance fromthe top-gate electrode 804 than the first drain region 810. The seconddrain region 820 has a greater extent in a depth direction than thefirst drain region 810. The extent in a depth direction of the seconddrain region 820 corresponds to the one of the first source region 808.

The second source region 818 is laterally electrically isolated from thefirst source region 808 by the first source isolation region 812. Inthis case, the extent in a depth direction of said first sourceisolation region 812 extends—in contrast to what is the case in theexemplary embodiment of FIG. 7—as far as to the lower edge of the firstsource region 808. The second source region 818 is laterallyelectrically isolated from the top-gate electrode 804 by a second sourceisolation region 822.

The second drain region 820 is laterally electrically isolated from thefirst drain region by a second drain isolation region 824. The seconddrain isolation region extends into the second depth section II and hasthe same extent in a depth direction as the first source isolationregion 812.

As can be clearly seen in FIG. 8, the first source region 808 has anextent TS1 in a depth direction T in the silicon body 802 which isgreater than the one of the drain region 810, which, accordingly, has asmaller extent TD1 in a depth direction. The extent TD1 in a depthdirection corresponds approximately to the doping depth of asource/drain region that is customary for the CMOS technology used.

In the following, the structure of the top-gate electrode 804 in itsenvironment is explained in more detail.

From a lateral point of view, the already mentioned second sourceisolation region 822 is arranged between the second source region 818and the top-gate electrode 804, wherein the second source isolationregion 822 electrically isolates the second source region 818 and thetop-gate electrode 804 from each other. An extent TIS2 in a depthdirection of the second source isolation region 822 into the first depthsection I of the silicon body corresponds to the extent in a depthdirection of the first drain isolation region 814 and extends as far asto the lower edge of the gate isolation layer 804.2.

From a lateral point of view, a first drain isolation region 814 isarranged between the first drain region 810 and the top-gate electrode804, wherein the drain isolation region 814 electrically isolates thedrain region 810 (and the entire drain electrode along with it) and thetop-gate electrode 804 from each other. The extent TID1 in a depthdirection T of the first drain isolation region 814 extends as far as tothe lower edge of the gate isolation layer 804.2, and also as far as tothe lower edge of the first drain region 810. Thus, the gate isolationregion 804.2 is arranged in a recess formed in the silicon body 802.

The first drain region 810 and the second drain region 820 areelectrically isolated from each other by a second drain isolation region824. The extent TID2 in a depth direction of the second drain isolationregion in the silicon body 702 corresponds to the ones of the seconddrain region 820, of the first source region 808 and of the first sourceisolation region 812, i.e. it extends as far as to the upper edge of thesecond depth section II.

The dimensions of the first and second source regions 808, 818, of thefirst and second drain regions 810, 820, of the first and second sourceisolation regions 812, 822, and of the first and second drain isolationregions 814, 824 in a depth direction are chosen such that, during theoperation of the two-channel semiconductor component, a first conductionchannel 802.1 is formed below the top-gate electrode 804 and a secondconduction channel 802.2, that is separated from the first conductionchannel 802.1, is formed above the bottom-gate electrode 806 in thesilicon body 802, when suitable control voltages UG1 and UG2 areavailable at the top-gate electrode 804 and the bottom gate electrode806. The two conduction channels 802.1 and 802.2 are separated from eachother by a barrier region 802.3 of the silicon body 802, which is formedwhen suitable gate voltages are chosen.

This means that, when a suitable first operating voltage UG1 is appliedto the top-gate electrode 804, the first conductive channel 802.1 of then-conductivity type, which is laterally separated from the first sourceregion 808 by the source isolation region 812, is formed in the firstdepth section I. The extent in a depth direction of said conductivechannel 802.1 can be influenced via the control voltage UG1 applied tothe top-gate electrode 804. This conductive channel 802.1 does not haveany direct contact with the source region 808, since, in a depthdirection T, it does not extend as far as to the lower edge of thesource isolation region 812. However, when wired in a suitable manner,the first conductive channel 802.1 establishes a conductive connectionbetween the second source region 818 and the first drain region 810.This means that, if necessary, the first conductive channel 802.1 can beoperated as the sole conductive channel of the component.

Furthermore, when a suitable second operating voltage UG2 is applied tothe bottom-gate electrode 806, a second conductive channel 802.3 of then-conductivity type is formed in the second depth section II of thesilicon body 802. The extent in a depth direction of said secondconductive channel 802.3 can be influenced via the control voltage UG2applied to the bottom-gate electrode 806. To put it more specifically:the voltage applied to the bottom-gate electrode 806 influences how farthe second conductive channel 802.2 extends “upwards”—in the directionof the top side of the silicon body—from the bottom side of the siliconbody 802. The second operating voltage UG2 is chosen such that thesecond conductive channel is only formed below the first source region808, but preferably extends as far as directly to the lower edge of thesource region 808. When wired in a suitable manner, the secondconductive channel 802.2 establishes a conductive connection between thefirst source region 808 and the second drain region 820. This meansthat, if necessary, the second conductive channel 802.2 can be operatedas the sole conductive channel of the component.

Thus, the conductive channels 802.1 and 802.2 can be controlledindependently of each other. However, it is also possible to operateboth conductive channels 802.1 and 802.2 in parallel.

Furthermore, in particular depending on the chosen operating voltagesUG1 and UG2, the following operating states can be set:

When respective first and second operating voltages are applied to thetop-gate electrode 804 and the bottom-gate electrode 806, a firstconductive channel 802.1, which is laterally separated from the sourceregion 808 by the first source isolation region 812 and from the seconddrain region by the second drain isolation region 824, is formed in thefirst depth section I, wherein said first conductive channel 802.1electrically connects the second source region 818 to the first drainregion 810. A second conductive channel 802.2, that is decoupled fromthe first conductive channel by a barrier region 802.3 of the siliconbody 802 extending in a depth direction between the conductive channels,is formed in the second depth section. The second conductive channelconnects the first source region 818 to the second drain region 820.

If the operating voltages UG1 and UG2 do not satisfy an adjustableresonance condition, this operating state corresponds to the decoupledstate shown in FIG. 3. However, charge carrier currents through theaforementioned two conductive channels can be controlled individually.

If the operating voltages UG1 and UG2 satisfy the adjustable resonancecondition, the first and second conductive channel 802.1 and 802.2 arecoupled to one another by means of a tunnel effect for electrons acrossthe barrier region 802.3 of the silicon body. This means that, in thiscase, charge carriers can also flow between the first source region 808and the second drain region 810, and between the second source region818 and the second drain region 820, namely respectively through thesecond conductive channel 802.2 by means of a tunnel effect through thebarrier region 802.3 and through the first conductive channel 802.1.

FIG. 9 shows a schematic cross-sectional view of the two-channelsemiconductor component 700 of FIG. 7 with circuitry for forming asignal mixer 900;

The signal mixer 900 is connected as follows:

The drain current ID at the output of the signal mixer 900, is, on theone hand, controlled at the source electrode by a high-frequency signalon the input side U_(D)(t), and, on the other, at the bottom-gateelectrode, by a local oscillator voltage ΔU(t). An output voltageU_(out)(t) , that corresponds to the product of the high-frequencysignal U_(D)(t) at the source electrode and the local oscillator voltageΔU(t) can be picked up at the drain electrode via a resistance R. FIGS.10 to 12 show corresponding exemplary signals. FIG. 10 shows anexemplary signal of a local oscillator voltage ΔU(t) as a function ofthe time in the form of a square wave signal, which can be supplied tothe signal mixer of FIG. 9 via its bottom gate electrode. FIG. 11 showsan exemplary signal of a high-frequency signal U_(D)(t) as a function ofthe time that can be supplied to the signal mixer of FIG. 9 in parallelvia the source electrode. FIG. 12 shows the resulting output signal thatcorresponds to the product of the two input signals of FIGS. 10 and 11.The signal of the local oscillator switches the signal mixerperiodically into a conductive and non-conductive state, so that theoutput signal corresponds to the product of the local oscillator signaland the input signal.

Such a signal mixer is particularly suitable for use in high-frequencycircuits, in particular for use in transmitter and receiver circuits forthe transmission of radio signals or optical signals by means of carrierwaves.

To sum it up: exemplary embodiments of a two-channel semiconductorcomponent were described. Said component has a doped semiconductor bodymade of a group IV semiconductor material, a top-side top-gate electrodeand a bottom-side bottom-gate electrode. A source region has a greaterextent in a depth direction in the silicon body than a drain region. Asource isolation region is arranged between a source region and thetop-gate electrode, and a drain isolation region is arranged between adrain region and the top-gate electrode, which isolation region extendsin a depth direction as far as to the lower edge of a gate isolationlayer of the top-gate electrode. In a first operating state a firstconductive channel separated laterally from the source region by thesource isolation region can be formed, as can a second conductivechannel, which is decoupled from the first conductive channel by abarrier region of the semiconductor body extending in a depth directionbetween the conductive channels. In a second operating state whichsatisfies a resonance condition, the first and second conductive channelcan be coupled to one another by means of a tunnel effect for minoritycharge carriers over the barrier region of the semiconductor body.

1. A two-channel semiconductor component, comprising: a dopedsemiconductor body formed from a group IV semiconductor material; atop-side top-gate electrode; a bottom-side bottom-gate electrode, afirst source electrode with a doped source region of a secondconductivity type—that is opposite to the first conductivity type—formedin the silicon body, a first drain electrode with a doped first drainregion of the second conductivity type formed in the semiconductor body;wherein the first source region has a greater extent in a depthdirection in the silicon body than the first drain region, and dividesthe silicon body into a first depth section, that extends as far as to alower edge of the first source region, and a second depth region thatextends in a depth direction adjacently to the first depth section asfar as to the bottom side of the semiconductor body; from a lateralpoint of view, a first source isolation region is arranged between afirst source region and the top-gate electrode, wherein said firstsource isolation region electrically isolates the source electrode andthe top-gate electrode from each other and extends in a depth directioninto the first depth section of the semiconductor body, but not into thesecond depth section; from a lateral point of view, a first drainisolation region is arranged between the first drain region and thetop-gate electrode, wherein said first drain isolation regionelectrically isolates the drain electrode and the top-gate electrodefrom each other and extends in a depth direction as far as to the loweredge of a gate isolation layer of the top-gate electrode; wherein therespective depth direction dimensions of the first source region, of thefirst drain region, of the first source isolation region and of thefirst drain isolation region are chosen such that in a first operatingstate, in which respective first and second operating voltages areapplied to the top-gate electrode and the bottom-gate electrode, a firstconductive channel of the second conductivity type, which is separatedlaterally from the first source region (808) by the first sourceisolation region, can be formed in the first depth section, and a secondconductive channel of the second conductivity type, which is decoupledfrom the first conductive channel by a barrier region of thesemiconductor body extending in a depth direction between the conductivechannels, can be formed in the second depth section, and in a secondoperating state, in which third and fourth operating voltages satisfyinga resonance condition are applied to the top-gate electrode and thebottom-gate electrode, the first and second conductive channel can becoupled to one another by means of a tunnel effect for minority chargecarriers over the barrier region of the semiconductor body.
 2. Atwo-channel semiconductor component according to claim 1, wherein theconductive channels have a channel length of between 5 and 30 nm.
 3. Atwo-channel semiconductor component according to claim 1, wherein thebarrier region has an extent in a depth direction of between 10 and 30nm.
 4. A two-channel semiconductor component according to claim 1,comprising a second source region, which is laterally arranged betweenthe first source region and the top-gate electrode, has a smaller extentin a depth direction than the first source region and is laterallyelectrically isolated from the first source region by the first sourceisolation region, and which is laterally electrically isolated from thetop-gate electrode by a second source isolation region, a second drainregion, which, from a lateral point of view, is arranged at a greaterdistance from the top-gate electrode than the first drain region, has agreater extent in a depth direction than the first drain region and islaterally electrically isolated from the first drain region by a seconddrain isolation region, and which extends into the second depth section,wherein the respective dimensions of the first and second source region,of the first and second drain region, of the first and second sourceisolation region and of the first and second drain isolation region in adepth direction are chosen such that the first conductive channelextends in the lateral direction between the second source region andthe first drain region, and that the second conductive channel extendsin the lateral direction between the first source region and the seconddrain region.
 5. The two-channel semiconductor component of claim 1,further comprising a signal mixer having a two channel semiconductorcomponent to which a first input signal is supplied via the bottom-gateelectrode, to which a second input signal is supplied via the sourceelectrode, and at the drain electrode of which an output signal can bepicked up via an output resistance.
 6. A detector component forelectromagnetic waves, comprising a two-channel semiconductor componentaccording to claim 1.